Only millions? What are we taking about then! Who cares, there is more time between the T-Rex and the Stegosaurus than there is between us and T-Rex (about 100 million more). And we have about 4000-5000 million years before the sun gives out.
https://en.wikipedia.org/wiki/Timeline_of_the_far_future#Ear...
Look at 500–600 million years. The sun's increasing luminosity means rising temperatures and falling CO2, which means no plant life at some point. The high estimate for plant and animal life is 1.2 billion years.
The sun swells to a red giant around 5 billion, swallows the Earth around 7.5, and shrinks to a white dwarf around 8.